1) I don't think so since you will need a gear that has a "freewheel" (look at White Industries, Shimano, probably others).
2) I'm not impressed with caliper brakes, but will try Kool Stop pads on mine to see if they're that much better than the Tektro that came with the brake.
3) The chain line could be a challenge, but you'll have some latitude with the freewheel mount on the hub.